Long day stimulation of dry matter production in Poa alpina along a latitudinal gradient in Norway

• Published in: Ecography
• Main Author: Solhaug, Knut Asbjørn
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1991
• Subjects: Ecology, Evolution, Behavior and Systematics; Arctic; Norway; Svalbard; Poa alpina; midnight sun
• Online Access: http://dx.doi.org/10.1111/j.1600-0587.1991.tb00648.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1600-0587.1991.tb00648.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-0587.1991.tb00648.x

Photoperiod extension with weak include from 8 to 24 h stimulated relative growth rate (RGR) of Poa alpina up to 20%. The response was greatest in young plants at low temperatures. The leaf area ratio (LAR) increased by about 50% which more than compensated for a reduction in net assimilation rate (NAR) by about 20%. The effect of daylength extension on RGR was similar for an arctic ecotype of P. alpina from Svalbard, an alpine ecotype from southern Norway and a borealtemperate ecotype from southern Norway. The main changes in the growth parameters occurred over the 13 to 17 h photoperiod range in P. alpina from both Svalbard and Rondane, although plants at Svalbard are exposed to midnight sun throughout their growing season. The ecotype of P. alpina from southern Norway had fewer tillers and allocated less dry matter to the roots than the two other ecotypes.